Circles: Area and Circumference 1st

What is the radius of this circle?

• 18
• 10
• 9
• 8

What is the diameter of this circle?

• 3.5
• 3
• 5
• 7

Is the red line a radius or diameter of the circle?

• Radius
• Diameter

The diameter is 40 inches.  What is the circumference?

• 62.8 inches
• 20pi inches
• 40pi inches
• 251.2 inches

The radius is 21 inches.  What is the circumference?

• 65.94 inches
• 21pi inches
• 42pi inches
• 32.97 inches

The radius is 6 inches.  What is the area?

• 6pi
• 36pi inches
• 9pi inches
• 3pi inches

The diameter is 10 inches.  What is the area?

• 31.4 inches
• 15.7 inches
• 314 square inches
• 78.5 square inches

What is the area of a circle?

• The distance around a circle.
• The space inside the circle.
• A line from side to side passing through the center.
• A line from the center to the side.

What is the formula for the area of a circle?

• A = π r ²
• A = 1/2 (π r ²⁾
• A = 2πr
• A = πd

What is the equation for the circumference of a circle?

• C=πr²
• C=lw
• C=2πr
• C=4(1/2)bh